docs: def ontologyConceptTree(self):
          """
          Returns a dict representing the skos tree
          Top level = {0:[top concepts]}
          Multi inheritance is represented explicitly
          """
          treedict = {}
          if self.all_skos_concepts:
              treedict[0] = self.toplayer_skos
              for element in self.all_skos_concepts:
                  if element.children():
                      treedict[element] = element.children()
              return treedict
          return treedict